Organo distannthianes and the preparation thereof

ABSTRACT

THIS INVENTION IS ONE OF NOVEL COMPOUNDS OF THE FORMULA   ((R)2-SN(-X)-S)N-(S(-X)(3-N))N-R&#39;&#39;   WHEREIN R AND R&#39;&#39; ARE HYDROCARBONS, X IS A HYDROCARBON BONDED TO A TIN ATOM THROUGH A SULFUR ATOM AND N IS AN INTEGER OF LESS THAN 4, AND OF HALOGEN-CONTAINING POLYMERS STABILIZED AGAINST THE DETERIORATIVE EFFECTS OF HEAT BY THE PRESURE THEREIN OF SAID NOVEL COMPOUNDS.

United States Patent Int. Cl. C07f 7/22 US. Cl. 260-4295 4 Claims ABSTRACT OF THE DISCLOSURE This invention is one of novel compounds of the forwherein R and R are hydrocarbons, X is a hydrocarbon bonded to a tin atom through a sulfur atom and n is an integer of less than 4, and of halogen-containing polymers stabilized against the deteriorative effects of heat by the presence therein of said novel compounds.

The present invention relates to novel sulfur-containing organotin compounds which find use as stabilizers for halogen-containing resins, particularly polymers or copolymers of vinyl chloride and vinylidene chloride.

This application is a divisional application of Ser. No. 801,825, filed on Feb. 24, 1969, now US. Pat. No. 3,609,120.

The invention is based on our discovery that a di-organotin sulfide of the formula R SnS wherein R is a hydrocarbon group or substituted hydrocarbon group will react with a mono organotin compound of the formula R'SnX wherein R is a hydrocarbon group or substituted hydrocarbon group and each X is an electro negative group bonded to the tin atom through a sulfur atom, to form a stannthiane.

We have found that the particular stannthiana produced depends upon the relative proportions of the diorganotin sulfide and the mono-organotin compound of the formula RSnX employed. Thus if equimolar proportions are used a distanuthiane is formed having the if a 1:2 molar ratio of R'SnX to R SnS is employed the product will be a compound having the formula:

3,778,456 Patented Dec. 11, 1973 'ice and if a 1:3 molar ratio of R'SnX to R SnS is employed the product will be a compound having the formula:

Bit

Should intermediate molar ratios be employed then a mixture of products will result. It is not believed that such mercapto substituted stannthianes have previously been described.

Accordingly, from one aspect the present invention provides stannthianes of the general formula:

wherein each R is a hydrocarbon or substituted hydrocarbon group or the two R groups, together with the tin atom may make up a 5 or 6 membered heterocyclic ring or R is a poly-valent hydrocarbon radical in a polymeric chain composed of recurring (-R-SnR-) groups, R is a hydrocarbon or substituted .hydrocarbon group; each X is an electro negative group bonded to the tin atom by a sulfur atom, and n is an integer from 1 to 3.

From another aspect the invention provides a process for the preparation of the stannthianes of the invention which comprises either reacting a diorganotin sulfide [R SnS] with an organotin compound of the general formula RSnX or a two stage process wherein a diorganotin sulfide [R SnS] is reacted with a compound of the formula R'SnZ wherein Z is an electro negative group such as a chloride or bromide, and the product of this reaction is reacted with a mercapto compound of the formula XH.

Organotin sulfides of the formula R SnS which may be used for preparing compounds according to the invention are those in which each R is a hydrocarbon group, or a substituted hydrocarbon group in which the substituent group is inert and the two R groups may be the same or diiferent. Suitable groups which may be bonded to the tin atom in the organotin sulfide are alkyl groups such as methyl, ethyl, propyl, butyl or octyl groups; aryl groups such as phenyl, tolyl and xylyl groups; cycloalkyl groups such as cyclohexyl or aralkyl groups such as benzyl. Preferred organotin sulfides for use in the process of the invention are dibutyltin sulfide, di-n-octyltin sulfide, di-2- ethylhexyltin sulfide, dicyclohexyltin sulfide and diphenyltin sulfide.

Organotin compounds of the formula R'SnX which may be used in processes according to the invention are those in which R, which may be the same as R or different is an alkyl group having from 1-16 carbon atoms, cycloalkyl, aralkyl or aryl group and may contain an inert substituent which will not cause donation or withdrawal of electrons from the tin atom and X is an electro negative group bonded to the tin atom by a sulfur-tin bond, and each X may be the same or different. Particularly suitable R groups include n-butyl groups, n-octyl groups, 2-ethylhexyl groups, iso-octyl groups, cyclohexyl groups and phenyl groups. The electro negative X group contains a sulfur atom which bonds to the tin atom and suitable groups include mercaptide groups such as the ethyl mercaptol and thiosorbitol residues or aryl mercaptol residues such as thiophenol, and thionaphthol residues and thiocarboxyl residues such as those derived from thiobenzoic acid. Particularly preferred, however, are the residues of mercapto-substituted carboxylic acid esters in particular of thioglycolate esters, fl-mercaptopropionate esters, and mercapto maleate esters.

Suitable compounds of the formula RSnX which may be used in the process of the invention include n-butyltin tristhiophenolate, cyclohexyltin tristhiophenolate, cyclohexyltin trisiso-octyl thioglycolate, n-butyltin trisdecylthioglycolate, octyltin trisnonylthioglycolate, cyclohexyltin trisiso-octylthioglycolate, phenyltin trislaurylthioglycolate, and n-butyltin trishexylthioglycolate. Especially preferred, however, are n-butyltin trisiso-octylthioglycolate, octyltin trisiso-octylthioglycolate, phenyltin trisiso-octylthioglycolate, n-butyltin trisiso-octylthioglycolate, n-butyltin trisiso-octyl p-mercaptopropionate, and octyltin trisisooctyl fl-mercaptopropionate.

The process of the invention may be carried out merely by mixing the two reactants, preferably in stoichiometric amounts and heating if necessary. Preferably, however, the process is carried out in the presence of a solvent for the organotin compound of formula RSnX which is inert to the reactants and product. Such a solvent is normally a hydrocarbon, a ketone or an ether. For example hexane, benzene, toluene, xylene, acetone, diethyl ether, dibutyl ether or tetrahydrofuran may be used. In order to reduce the length of time taken to bring the reaction to completion it may be found convenient to warm the reaction mixture, for example, to between about 40 C. and 80 C. for a short period. The desired product may then be obtained by distilling off the solvent.

Compounds according to the invention find use as stabilizers for compositions comprising polymers or copolymers of vinyl chloride or vinylidene chloride, chlorinated vinyl chloride polymers, and chlorinated polyethylene. While it will often be convenient to add the preformed compound to the polymeric resin, it may be desired to add the reactants to the resin and allow them to react in situ in the resin formulation. If this is done it may be desirable for certain applications to include an excess of either of the reactants over the amount required to form the desired reaction product in the polymeric composition.

Accordingly, from a further aspect, the present invention provides a composition which comprises a polymer or copolymer of vinyl chloride or vinylidene chloride, a chlorinated polymer of vinyl chloride or chlorinated polyethylene, and as a stabilizer therefor a mixture of, or the reaction product of, a compound of the formula RSnX with a compound of the formula RSnS wherein R, R and X are as hereinbefore defined.

If it should be desired to form the stannthianes of the invention in situ in the polymeric composition this may be accomplished by adding the reactants to particles of the desired resin prior to milling.

Specific combinations of compounds which are of use in compositions according to the invention, either in admixture or as the reaction products are: mono-n-butyltin trisiso-octyl thioglycolate and di-n-butyltin sulfide, believed to react to form 1,l,S-tri-n-butyl-1,3,3-tris-iso-octylthioglycolate 1,3 distann 2 thiane; mono-octyltin trisiso-octylthioglycolate and dioctyltin sulfide believed to react to form 1,1,3-trisiso-octylthioglycolate 1,3 distann- 2 thiane; phenyltin trisiso-octylthioglycolate and dibutyltin sulfide believed to react to form 1,1-dibutyl-3-phenyl- 1,3,3 tris-iso-octylthioglycolate 1,3 distann Z-thiane;

mono-n-butyltin trisiso-octylthioglycolate and dioctyltin sulfide reacting to form 1,1 dioctyl 3 n-butyl 1,3,3- tris-iso-octylthioglycolate-1,3-distann-2-thiane.

Other useful combinations include mono-cyclohexyltin trisiso-octylthioglycolate and dibutyltin sulfide; n-butyltin tris-laurylthioglycolate and dibutyltin sulfide; octyltin trislaurylthioglycolate and dioctyltin sulfide; mono-cyclohexyltin trisiso-octylthioglycolate and dioctyltin sulfide; phenyltin tris-laurylthioglycolate and dibutyltin sulfide; and n-butyltin tris-hexylthioglycolate and dibutyltin sulfide, mono-n-butyltin trisiso-octyl S-mercaptopropionate and dibutyltin sulfide; and mono-n-octyltin trisiso-octyl fl-mercaptopropionate and dioctyltin sulfide.

The combination of organotin compounds will be present in compositions according to the invention in amounts from 2% to 3% by weight based on the total amount of polymeric resin present.

Optionally, but advantageously, compositions according to the invention also contain hindered phenols, that is those having at least one substituent in a position ortho to the hydroxyl group. Such phenols which are of use in compositions of the present invention include butylated hydroxyanisol, 2,6-di-tert-butylphenol,

methylene bis(2,4-di-tert-butylphenol), methylene bis(2,6-di-tert-butylphenol), methylene bis(2,6-di-tert-butyl-3-methylphenol), 4,4'-butylidene-bis(6-tert-butyl-3-methylphenol), methylene bis(4-ethyl-6-tert-buty1phenol), methylene bis(4-methyl-2,G-di-tert-butylphenol).

Particularly preferred, however, is 2,6-di-tert-butyl-4 methylphenol. Such phenols may be present in an amount of up to 3%, preferably from 0.01% to 0.5% by weight of the resin and will normally be presentas about 4%- 10% by weight, preferably 5%-8%, based on the total amount of organotin compounds used.

Organotin formulations as described above, optionally including a hindered phenol, will often be used as the only stabilizer in a polymeric vinyl chloride or vinylidene chloride composition. However, if desired conventional thermal stabilizers may also be included. These may include, for example, metal soap stabilizers such as cadmium, barium or zinc salts of fatty acids, or lead salts such as lead carbonate or stearate or dibasic lead phosphate or phthalate, or tribasic lead sulfate or conventional organotin stabilizers such as dibutyltin dilaurate or dibutyltin maleate or sulfur-containing compounds such as dibutyltin bis-thioglycolates.

In the practice of the invention the stabilizer formulation may be mixed with the halogen-containing resin in the conventional manner, for example, by milling with the resin on heated rolls at about 0., although higher temperatures may be used when convenient, or by being mixed with particles of the polymer and then melting and extruding the mixture or by adding the stabilizer to a liquid resin.

Resins which may be used in compositions according to the invention normally contain at least 40% by weight of chlorine. Usually it will be a polymer or copolymer of vinyl chloride or vinylidene chloride but posthalogenated polyvinyl chloride or post-halogenated polyolefins, such as polyoethylene, may be employed if desired. Suitable monomers which may form such copolymers with vinyl chloride and vinylidene chloride include, for example, acrylonitrile, vinyl acetate, methyl methacrylate, diester of fumaric acid, and maleic acid, ethylene, propylene, and lauryl vinyl ether and these co-monomers may be present in an amount of up to 25% of the total weight of monomers copolymerized.

The organotin stabilizer formulation may be employed in either plasticized resin compositions, for example, those plasticized with carboxy ester plasticizers or may be employed in unplasticized, that is rigid, compositions.

6 The process of the invention will be illustrated by the bis(isooctylthioglycolate) were prepared as in Example following examples: 6 using a commercial polymer Breon 202 (vinyl chlo- EXAMPLE 1 ride+vinylidene chloride copolymer) and a commercial polymer Kureka HC825L (vinyl chloride-I-fumaric acid A mixture of dlbutyltm sulfide (40 parts wt.) and copolymer). Colors of the heat aged samples of the hides mono-butyltin trisiso-octylthioglycolate (118 parts) was are indicated in Table II.

TABLE II n Color of degraded polymer Compound Polymer Initial 201 51 got 1 Contr Breon Colorless. Pale yellow-.... Yellow Dark yellow- Yellow brown- Red. Example 1 on do Colorless Pale brown--. Pale brown.-- Brown Dark brown. Control-.... Kureka HC825L P818 y ll w"... Pale yellow... Yellow Dark yellow Orange. Example 1 do do do do Pale yellow... Pale yellow-.--. Pale yellow.

Time (minutes) at 200 C.

stirred and heated to 80 C. 2,6-di-ter Y -P' Although this invention has been illustrated by referp j was added and the product s removed by ence to specific embodiments, modifications thereof which filtration to give a clear almost colorless llqllld (found: 20 are clearly within the scope of the invention will be ap- Sn" 21.1%, S 10.3%). parent to those skilled-in-the-art.

x Q N What is claimed is: E PLE 2 1. A compound of the formula A mixture of dioctyltin sulfide (37.7 parts wt.) and R octyltin trisiso-octylthioglycolate (84.2 parts) were heated to 80 C. 2,6-di-tert-butyl-p-cresol (6 parts wt.) was added 'nS-Sn-R' and the mixture stirred at 80 C. for minutes and R X A filtered. h

EXAMPLE 3 w ereln R and R are 1nd1vidually selected from the group 30 consisting of alkyl radicals containing between one and A stabilizer was prepared from dibutyltin sulfide (25.6 sixteen carbon atoms, cycloalkyl, aralkyl and aryl radiparts wt.), mono-butyltin trisiso-octyl p-mercapto-propicals which may be inertly substituted, X represents a monoonate ('83 parts) and 2,6-di-tert-butyl-p-cresol (5.8 parts valent radical exhibiting a formula selected from the wt.) as described in Example 1. group consisting of EXAMPLE 4 o A stabilizer was prepared from mono-butyltin trisisoand octylthioglycolate (78.5 parts wt.) dioctyltin sulfide (37.6 parts) and 2,6-d1-tert-butyl-p-cresol (5-8 Part5 as wherein R' represents a methylene or an ethylene radical descr be 111 Example and R" represents a radical selected from the same group EXAMPLE 5 as 2. A method for preparing organotin compounds of the A stabilizer was prepared from dibutyltin sulfide (26.5 general formula parts wt.), mono-phenyltin trisiso-octylthioglycolate (80.5 R parts) and 2,6-di-tert-butyl-p-cresol (5.35 parts wt.) as \s S S R described in Example 1. n 1km- R x m -m EXAMPLE 6 in substantially pure form wherein R and R are individ- Use of stabilizers 1-5 in polyvinyl chloride, ually selected from the group consisting of alkyl radicals The stabilizer (2 parts wt.) was milled at 150 C. for contammg between one and sixteen carbon atoms, cyclo- 10 minutes with 0 Parts of Polyvinyl id alkyl, aralkyl and aryl radicals which may be inertly sub- (Corvic 9 Samples f the milled polyvinyl 1 strtuted, X represents a monovalent radical exhibiting a ride hide were oven aged at 200 C. in air. Colors of formula Selefled from the group consisting of the oven aged sheet are indicated below in Table I. The 0 standard (control) test specimen contained 2 parts wt. 1! m 55 and of dibutyltm b1s(1sooctylth1oglyco1ate) per 100 parts of H the same polymer. OR

TABLE I Color of degraded PVC Time at 200 C. for.. Inltial 15 min. 20 min. 25 min. 30 min. 35 min. 40 i Com ound:

ontrol.-.-.-..;. Colorless--'.--'.'-.. Yellow...-:-:-:- Yellow...-.;-::.; Darkye1low. Omnoo Dark m1 Black Example:

1 .-....-.-....do Colorless Colo ess Pe1ebrown-...- Pale brown Pale brown pale brown,- 2 do do do Pale yellow..--- Yellow Yellow brown- Do. a rin do do Pale brown...-- Pale brown Pale brown.- Do. 4 a do do Colorless do do Do. 5 do do Pale brown.-..- Brown Greenlsh brown. Dark green.--.-.. Black.

EXAMPLE 7 v m wherem R represents a methylene or an ethylene radical, Fee of Su me x p 1 Polyvlnyl chlonde R" represents a monovalent hydrocarbon radical selected po ymers.

Polymer hides containing 2 parts wt. of the stabilizer from the same group as and m represents the integer were prepared in Example 1 and, 2 parts wt. of dibutyltin 1, 2, or 3, said method comprising reacting a substantially 3,778,456 7 8 stoichiometric amount of a diorganotin sulfide with an References Cited organotin compound of the general formula R'SnX 3. The method of claim 2 wherein R and R are indi- UNITED STATES PATENTS vidually selected from the group consisting of butyl and 3,565,930 2/1971 Kauder 260429] octyl radicals, R" is an isooctyl radical and R represents Y a methylene or an ethylene radical. 5 WERTEN F. W. BELLAMY, Primary Examlner 4. The method of claim 2 wherein a hindered phenol comprises between 4 and 10% by weight of the organotin compounds present in the reaction mixture. 260 45-75 K v I UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3.778 .456 Dated December 11, 1973 Inventor(s) PETER ALBERT THEODORE HOYE and DONALD ALBERT WOOD f It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

' Column 1, line 6 Change "Albright & Wood Limited" to -Albright 81 Wilson Limited-- Signed and sealed this 23rd day of April 197L I SEAL -At te s t EDI/JARD l I .FL ETCHER JR C MARSl-IA LL DANI-I Attesting Officer Commmssioner of Patents FORM Po-1o5o (10-69) USCOMM-DC 6O376-F69 U.S. GOVERNMENT PRINT NG OFFICE l9, 0-366-3. 

